How Wood Stoves Work

The venting system, or stovepipe and chimney, is one of the most im­portant components of your wood stove installation. A well-installed pipe makes all the difference between an efficient stove and an ornamental one.

Some common ways homeowners run into problems:

Retrofitting an old chimney: Frequently, old chimneys are too big for today's wood stoves. That means the amount of air they draw is not proportional to the amount of heat the stove produces. A too-big chimney means you'll burn more wood than you need, and likely spend more time than necessary on fire maintenance. You'll need to install a "liner" stovepipe within the chimney. It should run the entire length of the chimney, and nowhere along its length should it be any bigger than the stove's exhaust opening. But -- before you go jamming pipe up the chimney -- you should know how the chimney was built, and what sort of insulation it contains. The heat produced by a wood-burning stove is different from the heat produced by an open fireplace, and your chimney may not be up to the task without some work.

Setting the stovepipe to minimum height requirements: A short chimney may look nicer (though that's a matter of opinion), but it may not supply an optimal draft to the stove. Work with a professional to figure out the right stovepipe height for your stove.

Running too much horizontal stovepipe: A venting system works best when it's vertical. Some homeowners, rather than create chimney holes in the roof, run stovepipe out windows or through walls. But this is a very bad idea.

Running the stovepipe along an exterior wall: This isn't a safety issue so much as an efficiency issue. The stove will heat more of the house if the pipe travels up along an interior wall, so all the heat from the pipe stays in the house.

Not installing a vent to the exterior: This one should be obvious -- it's a good idea for the exhaust to wind up outside your house.

Creating too many twists and turns: Venting systems should be direct and straight. Twists and turns in a stovepipe invite the buildup of creosote, and that raises the risk of fire [sources: EPA, Wood Heat Organization, Chimney Sweep Online].

As always, a professional can help you get the stovepipe right. On the next page, we'll look at another good reason to consult a professional -- the safety risks of wood stoves.

Insulation

As long as you're installing your stove, why not give your home a thorough energy audit? Do you have energy-efficient windows? Have you caulked all cracks? How well are the walls insulated? Does every door and window have sound weather-stripping? The federal ENERGY STAR program can help you find opportunities to get the most for your heating dollar.­